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QP44.H14  A  laboratory  guide  i 


RECAP 


A  LABORATORY  GUIDE 
N  PHYSIOLOGY 
IHAPTERS  I.  AND  II.  ON  CIRCULA- 
TION AND  RESPIRATION 

WiNFIELD  S.  HALL 


Columbia  ®mtiersfit|> 
in  tfje  Citj»  of  i0eto  gorfe 

COLLEGE  OF  PHYSICIANS 
AND   SURGEONS 


Reference  Library 

Given  by 


c5^ce</«vt*><»  ^  Xy"*^ 


LABORATORY  GUIDE 


PHYSIOLOGY 


CHAPTERS  1.  AND  II. 
ON  CIRCULATION  AND   RESPIRATION. 


WINFIELD  S.  HALL,  Ph.  D.,  M.  D., 

PROFESSOR  OF  PHYSIOLOGY,  NORTHWESTERN   UNIVERSITY   MEDICAL  SCHOOL 

CHICAGO. 


CHICAGO  : 
THE   W.  T.   KEENER   CO. 

iSg6. 


Copyright,  1896, 
By  Winfield  S.  Hall. 


N 


PREFACE. 

American  laboratories  of  phjsiolog}'  have  usually  been 
established  in  medical  schools  after  these  institutions  have 
already  associated  histology  with  pathology,  and  physio- 
logical chemistry  with  general  chemistry.  The  problems 
presented  in  those  American  laboratories  of  physiology 
wliicli  are  departments  of  medical  schools  are,  therefore, 
essentially  the  physical  problems  of  physiology.  It  is, 
then,  quite  unnecessary  to  burden  the  student  with  the 
purchase  of  a  voluminous  manual  largel}'  devoted  to  mor- 
phology and  to  the  chemical  problems  of  ph}  siology.  The 
student  who  has  but  four  years  to  devote  to  the  study  of 
medicine  cannot  consistently  be  assigned  more  than  100 
hours  to  120  hours  of  laboratory  work  in  physical  physi- 
olog)'.  How  to  most  profitably  spend  this  brief  period  is 
a  question  which  has  engaged  the  attention  of  the  writer 
for  a  number  of  years.  In  the  choice  of  the  work  to  be 
assigned  to  the  student  it  has  been  taken  for  granted  that 
he  has  entered  upon  his  study  of  medicine  with  a  knowl- 
edge of,  at  least,  the  rudiments  of  phj'sics  and  of  algebra, 
and  that  laboratory  work  in  physiology  is  not  begun  until 
the  student  has  made  considerable  progress  in  gross  and 
minute  anatomy.  Courses  in  anatomy  and  physiology 
should  be  so  coordinated  as  to  enable  the.  student  to  gain 
a  thorough  knowledge  of  the  morphology  of  an  organ  be- 
fore he  experiments  upon  its  function. 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 
Columbia  University  Libraries 


http://www.archive.org/details/laboratoryguidei1896hall 


INTRODUCTION. 


THE  METHOD  OF  PRESENTING  THE  SUUJKCT. 

IHK    (jri-.S'lION    OF    ILLUSTRATIONS. 

The  profuse  illustration  of  a  text-book  is  in  perfect  ac- 
cord with  the  principles  of  pedagogy  ;  that  the  profuse 
illustration  of  a  laboratory  manual  is  the  reverse  is  evi- 
dent from  the  following  considerations: 

The  laboratory  student  receives  from  the  demonstrator 
the  material  with  which  he  is  to  work.  If  he  receives  a 
piece  of  apparatus  which  is  new  to  him,  a  few  questions 
or  hints  in  his  laboratory  manual  will  lead  him  to  discover, 
from  an  examination  of  the  apparatus  itself,  the  physical 
and  mechanical  principles  involved  and  utilized  in  it.  Most 
students  will  spontaneously  make  drawings  showing  the 
essential  parts  of  the  instruments  ;  all  students  will  will- 
ingly do  so  if  required.  This  is  a  most  valuable  exercise 
for  the  pupil,  which  is  likely  to  be  omitted  if  the  manual 
contains  cuts  of  the  apparatus. 

Nearly  every  exercise  requires  the  preparation  of  some 
simple  appliance — e.  g.,  a  frog  board  or  a  recording  lever 
— whose  construction  will  be  much  facilitated  if  the  stu- 
dent is  guided  by  a  figure  in  his  manual,  but  a  model 
which  the  demonstrator  has  made  will  be  a  better  guide. 

I  have  often  seen  students  read  their  text  descriptive 
of  some  organ — e.  g.  a  frog  heart — and  verify  its  state- 
ments from  the  accompanying  figures,  leaving  almost  un- 
noticed the  object  itself,  which  lay  before  them.  A  few 
brief  questions  or  hints  would  have  led  them  to  discover 
on  the  object  all  of  its  essential  features.  Diagrammatic 
anatomical   figures   are   sometimes  useful    in   a  laboratory 


6  LABOR  A  TOR  \ "  G  UIDE  IN  PHYSIOL  O  G  Y. 

manual,  but  true  anatomical  figures  are  worse  than  use- 
less— they  bar  the  student's  independent  progress.  If  his 
laboratory  manual  contains  illustrations  of  all  apparatus 
and  tissues,  and  of  such  experiments  as  admit  of  graphic 
records,  the  student  makes  similar  drawings  in  his  notes, 
either  unwillingly  or  dependently — frequently  both.  The 
laborator}'  work  is  thus  robbed  of  much  of  the  benefit  it 
is  intended  to  give  the  student.  Independence  and  origi- 
nality are  completely  defeated  or  aborted,  except  in  the 
case  of  the  rare  student. 

If  the  laboratory  manual  contains  graphic  records  of  an 
experiment,muchof  the  time  of  the  demonstrator  will  be  con- 
sumed in  explaining  to  the  students  individually  why  the 
same  physiological  functions  observed  with  slightly  differ- 
ent apparatus  and  under  slightly  different  circumstances, 
may  differ  in  minor  detail  from  the  tracings  in  the  book. 
The  energies  of  the  demonstrator  will  thus  be  partially  di- 
verted from  their  legitimate  channel.  If  there  is  no  trac- 
ing in  the  text,  students  will  naturally,  by  comparison  of 
their  tracings,  discover  the  essential  and  the  nonessential, 
and  the  cause  of  the  essential  features  of  these  tracings. 
After  the  student  has  made  these  independent  discoveries 
he  is  in  a  position  to  gain  the  maximum  profit  from  the 
comparison  of  his  own  tracings  with  those  which  others 
have  taken,  and  from  any  explanations  which  the  demon- 
strator may  choose  to  add. 

It  is  evident  then,  that,  from  a  pedagogical  standpoint, 
the  laboratory  guide  should  be  very  sparsely  illustrated,  if 
at  all.  On  the  other  hand,  the  student's  notes  should  be 
profusely  illustrated. 

THE    QUESTION    OF    EXPLANATION. 

What  has  been  said  regarding  the  illustrations  of 
apparatus  and  of  results  applies,  in  principle,   to  the  ex- 


LABoKAl  OKV  iJUJi>E  J\  I'JI  V  SlULUGY.  7 

planalioii  of  physiological  observations.  As  wheat  is 
more  valuable  than  clia'^f,  so  is  the  independent  discovery 
of  a  principle  by  the  student  more  valuable  to  him  than 
its  explanation  b\'  a  book  or  instructor.  If  the  facts  to 
be  observed  and  the  principle  involved  be  detailed  and 
explained  in  advance,  the  student's  power  of  independent 
observation   and   investigation   remains   undeveloped. 

THE    FUNCTION    OK    THE    DEMONSTRATOR. 

It  may  be  well  to  introduce  this  topic  by  a  state- 
ment of  what  the  function  of  the  demonstrator  is  not.  It 
certainly  is  not  to  rob  the  student  of  the  pleasure,  exhila- 
ration and  benefit  of  independent  investigation  of  a  prob- 
lem by  introducing  each  laboratory  period  with  an 
enumeration  of  the  facts  and  principles  which  the  work  of 
the  day  is  expected  to  establish.  Such  an  introduction  is 
worse  than  useless.  The  desirabilit}'  of  even  asking  the 
attention  of  the  entire  class  to  introductor}'  remarks  on 
the  general  bearing  of  the  problem  in  hand  is  to  be  ques- 
tioned. If  the  problem  is  well  chosen  and  the  work  in  the 
physiological  laboratory  properly  coordinated  with  that  in 
the  recitation  room  and  lecture  room  and  that  in  other  de- 
partments, its  significance  will  at  once  be  evident  to  the 
intelligent  pupil.  If  the  introductory  talk  is  omitted  the 
prompt  student  may  begin  at  once,  upon  entering  the 
laboratory,  the  problem  of  the  day  and  will  have  a  clear 
gain  of  ten  to  twenty  minutes.  Any  supplementary 
instruction  or  hint  may  most  profitably  and  economically 
be   written   upon  the  blackboard. 

Most  of  the  experiments  given  in  this  book  cannot 
conveniently  be  performed  by  one  individual  working 
alone.  After  some  experimentation  it  has  been  found  most 
advantageous  to  divide  the  class  into  sections  not  exceed- 
ing  thirty   students,  and   to  subdivide  these  sections  into 


8  LABORATORY  GUIDE  IN  PHYSIOLOGY. 

divisions  of  three  students  each.  Each  division  is  assigned 
a  table.  The  assistant  demonstrator  places  the  material 
needed  for  any  day's  work  either  upon  the  tables  or  where 
it  is  readily  accessible. 

Nothing  should  be  done  for  the  student  which  he  can 
profitably  do  for  himself.  A  small  class  with  less  limited 
time  may  easily  construct  much  apparatus  in  the  work- 
shop. No  class  is  so  large  as  to  debar  the  members  from 
the  privilege  of  constructing  frog-boards,  tracing  levers, 
etc.,  (which  may  be  done  at  the  tables)  and  of  setting  up, 
adjusting  and  readjusting  all  apparatus. 

Nothing  should  be  told  a  student  which  he  can  readily 
find  out  for  himself.  The  function  of  the  demonstrator 
is  to  guide  the  student  by  questions  and  by  hints  to  dis- 
cover facts  and  to  formulate  principles.  Extended  expla- 
nations on  the  part  of  the  demonstrator  may  instruct  the 
student,  but  they  do  not  educate  him. 

HINTS    TO    THE    STUDENT. 

It  is  a  general  principle  that  a  student  gets  out  of  a 
course  what  he  puts  into  it,  and  with  interest.  If  he  in- 
vests (1)  intellectual  capacity,  (2)  the  spirit  of  inquiry 
and  investigation,  (3)  the  power  of  logical  reasoning,  and 
(4)  the  power  to  formulate  conclusions  ;  he  will  promptly 
receive  interest  upon  the  investment.  Further,  the  greater 
the  investment  the  greater  the  rate  of  interest.  This  may 
seem  inequitable,  but  it  is  inevitable. 

The  value  of  taking  full  notes  of  laboratory  experi- 
ments is  unquestionable.  The  following  hints  regarding 
note  taking  may  be  advantageous  : 

1.  Make     a   careful     description    of   each   new   instrument 

with  which  you  work. 

2.  Formulate  each  problem  definitely. 

3.  Describe    the    means    used    in     the     solution     of    the 

problem. 


/..uu>h\rroh-y  cuini-:  i.\  riiysioi.ocv.  9 

4.   Enumerate    the   facts  observed  throu[^h  the  help  of   the 

means  employed. 
f».    Seek     for  and   note    causes    and   inter-relations  of  the 

facts  as  far  as  possible. 
G.   Differentiate  the  essential  from  the  incidental. 

7.  Formulate  conclusions  from  the  collected  data. 

8.  Make  generalizations  as  far  as  they  are  justifiable. 

A  good  notebook  should  possess  the  following  qualities: 
(7.    It  should    be  complete,   containing  an  account  of   every 
problem  studied. 

b.  It    should    be    full,    containing    a   sufficient    amount  to 

guide  another  in  performing  the  same  experiments 
and  in  verifying  the  facts  and  conclusions  noted. 

c.  It  should  be  logically  arranged. 

d.  It  should   be  as   neat   and    artistic   as  the  student   can 

make  it  in  the  time  which  he  can  devote  to  it. 
Such    a   notebook  is  a  most   valuable   addition   to   any 
library,  but  the  simple  making  is  still  more  valuable  to  the 
one  who  does  it. 


A.   CIRCULATION. 


I.     THE  CIRCULATION  AND  ITS  ULTIMATE  CAUSE. 

a.    To  observe  the  capillary  circulation  : 

1.  Appliances  needed. — Cork-board  8   cm.   wide  by  20  cm. 

long  and  about  ^  cm.  thick;  cover  glasses,  18  mm. 
in  diameter  and  10  mm.  in  diameter  ;  normal  salt  so- 
lution ;  camel's  hair  brush;  pins;  compound  micro- 
scope; sealing  wax;  thread;  filter  paper;  2  per  cent 
croton  oil  in  olive  oil. 

2.  Preparation. — Pith  two  frogs  the  day  before  the    obser- 

vation is  to  be  made.  At  the  beginning  of  the  labora- 
tory period  when  the  observation  is  to  be  made  curar- 
ize  the  frog  lightly  by  the  hypodermic  injection  of  one 
drop  of  a  1  per  cent  solution  of  curari.  Make  a  frog- 
board  by  cutting  a  hole  1.5  cm.  in  diameter  near  one 
corner  of  the  cork-board  and  fasten  a  large  cover  glass 
over  the  hole  with  sealing  wax. 
j>.  The  operation. — After  the  frog  becomes  curarized,  pin 
it  out  ventral  surface  downward  in  such  a  way  as  to 
bring  one  of  the  hind  feet  over  the  hole  in  the  board. 
Tie  thread,  not  too  tightly,  to  the  third  and  fourth 
digits,  loop  the  threads  over  pins  and  gently  separate 
the  digits  until  the  web  is  quite  flat  and  closely  ap- 
proximated to  the  surface  of  the  fixed  glass  which 
covers  the  hole.  Run  a  film  of  normal  salt  solution 
under  the  web;  place  a  drop  of  the  same  liquid  upon 
the  upper  surface  of  the  web;  place  a  small  cover 
glass  over  it;  fix  the  board  upon  the  microscope  stage 
so  as  to  admit  of  illumination  by  transmitted  light; 
illuminate  ;  focus. 


LABORATORY  GUIDE  l\   /'// VS/OLOG  V.  11 

^.    0/>S(-r7'(i//(>//s. 

(1)  Is  there  evidence  of  matter  in  motion?  Is  the 
moving  matter  liquid  or  solid?  If  the  matter  is  con- 
fined to  particidar  channels;  are  they  all  alike?  If 
not,  describe  differences. 

(2)  Observe  whether  the  motion  is  equal!}'  rapid  in  all 
channels;  if  not,  observe  whether  the  slower  currents 
are  in  the  larger  or  the  smaller  channels.  Deter- 
mine which  of  the  channels  are  arterioles,  which 
capillaries,  and  which  venules. 

(3)  Have  you  seen  evidence  of  an  intermitt(  nt  force 
acting  upon  the  moving  bodies?  If  so,  describe  its 
influence  and  location  minuteh'. 

(4)  Do  the  moving  bodies  change  shape?  If  so.  under 
what  circumstances  ? 

(5)  Remove  the  cover  glass,  dry  the  web  with  filter 
paper,  touch  a  point  with  a  pin  that  has  been  dipped 
into  dilute  croton  oil.  Observe  whether  the  pres- 
ence of  the  croton  oil  effects  any  change  in  the 
diameter  of  the  vessels,  or  in  the  rate  of  the  blood 
flow.  If  there  is  a  change  in  both,  has  one  a  causa- 
tive relation  to  the  other  ? 

(6)  Note  and  describe  minutely  all  changes  which 
take  place  at  and  near  the  place  touched  with  the 
croton  oil.  If  no  marked  change  is  produced  b}- the 
croton  oil,  touch  the  point  with  a  glass  point  which 
has  been  dipped  into  HNO.j. 

(7)  Have  you  noted  diapedesis  of  white  or  of  red  cor- 
puscles; if  so,  describe  the  process  minutely. 

2.     />.    To  obseri'c  the  action  o/  the /roi:;'s  heart  : 
I.  Appliances. — Dissecting     board  ;     fine    scissors  ;     heavy 
scissors  ;    pins  ;   forceps  ;  watch  glass  ;    camel's    hair 
brush  ;  normal  salt  solution  ;  fine  silk  thread  ;  ice,  in  a 
beaker. 


12  LABORATORY  GUIDE  IN  PHYSIOLOGY. 

2.  Preparation. — Pith  a  frog,  lay  it  with  its  dorsal  surface 
upon  the  dissecting  board  ;  stretch  out  its  legs  and 
pin  the  feet  to  the  board. 

J.  Operation. — Make  a  median  incision  through  the  skin 
from  the  pelvis  to  the  mandible  ;  make  transverse  in- 
cisions and  pin  out  the  flaps.  Raise  the  tip  of  the 
episternum,  insert  a  blade  of  the  fine  scissors  under  it 
and  divide  it  transversely,  about  ^  cm.  anterior  to  the 
tip.  Raise  the  anterior  segment  of  the  sternum  at 
the  point  of  the  transverse  incision  \  insert  the  blade 
of  the  strong  scissors  under  it  and  divide  it  longitu- 
dinally in  the  median  line.  Withdraw  from  the  board 
the  pins  which  fix  the  anterior  extremities,  make 
gentle  lateral  traction  upon  the  fore  feet  until  the  split 
sternum  is  sufficiently  separated  to  afford  a  convenient 
working  distance  and  to  plainly  expose  the  whole 
heart. 

4.    Observations. 

(1)  Note  rate  of  systole. 

(2)  Note  sequence  of  contraction  of  auricles,  ventri- 
cle and  bulbus. 

(3)  Note  change  in  shape  of  different  parts. 

(4)  Note  change  in  color  and  the  position  of  this  color 
change  in  the  heart  cycle. 

(5)  Carefully  excise  the  heart  including  the  sinus 
venosus  and  the  bases  of  the  posterior  and  two  an- 
terior venae  cavae,  also  the  bases  of  the  two  aortic 
trunks.  Place  the  excised  heart  in  a  watch  glass. 
Observe  whether  the  pulsation  continues.  If  so, 
what  is  your  conclusion  regarding  the  relation  of  the 
heart  movements  to  the  central  nervous  system. 

(6)  If  the  pulsation  continues,  note  whether  the  rate 
of  pulsation  has  been  noticeably  changed  by  the 
excision. 


LAHOKAIOKY  CUIDI:   /X  PHYSIOLOGY.  V<\ 

(7 )  Bathe  the  heart  with  a  few  drops  of  NaCl  solution, 
hold  the  watch  glass  in  the  palm  of  tiie  hand  and 
note  whether  the  rate  changes. 

(8)  Float  the  watch  glass  upon  ice  water  and  note  the 
results. 

(0)  If  the  heart  seems  vigorous  (otherwise  procure  a 
fresh  one),  carefully  sever  the  sinus  venosus  with 
the  fine  scissors.  Does  the  sinus  continue  to  beat  ? 
Does  the  heart  continue  to  beat  ?     Interpretation. 

(10)  If  the  heart  beats,  sever  the  auricle  from  the  ven- 
tricle through  the  auriculo-ventricular  groove.  Note 
results. 

(11)  If  the  auricles  beat,  divide  them.  If  they  con- 
tinue to  beat,  do  they  follow  the  same  rhythm  ? 

(12)  If  the  ventricle  becomes  quiescent,  stimulate  it 
either  mechanically  or  with  n  single  induction  shock. 
How  does  it  respond  to  a  single  stimulus?  Con- 
tinue to  subdivide  the  heart  until  the  parts  refuse 
to  respond  to  stimuli. 

(13)  Repeat  the  experiment  and  see  if  the  same  results 
are  reached  on  subsequent  trials.  Note  results  and 
give  yonr  interpretation. 


II.  THE  GRAPHIC  RECORD  OF  THE  FROG'S  HEART 

BEAT. 

1.  Appliances.— Yxog-hozxA\    a  straw  or  strip   of   bamboo 

20  cm.  long ;  a  cork  about  2  cm.  in  diameter  and 
height;  pins;  needles;  sealing  wax;  parchment  paper; 
a  kymograph,  stand  and  lamp. 

2.  Preparation. — Pith  a  curarized  frog.    Make  a  heart  lever 

after  the  model  shown  by  the  demonstrator. 

J.  Operation. — Open  the  abdomen  of  the  frog  as  described 
under  I-b-3  and  expose  the  heart.  Open  the  peri- 
cardium, place  some  resistent  object — a  cover  slip,  for 
instance — under  the  ventricle.  So  adjust  the  heart 
lever  that  the  cork  foot  of  the  long  arm  of  the  lever 
will  rest  upon  the  juncture  of  the  auricles  and  ventri- 
cles. If  the  weight  of  the  lever  seems  to  be  too  great 
for  the  heart  to  move  easily,  the  long  arm  may  be  made 
lighter  by  placing  a  counterpoise  upon  the  short  arm. 
If  the  tracing  point  of  the  long  arm  has  a  sufficient  ex- 
cursion to  make  a  good  tracing,  bring  the  kymograph 
to  a  position  where  the  point  will  lightly  touch  the  car- 
boned  surface  of  the  drum.  The  lever  should  be 
nearly  tangent  to  the  surface  of  the  drum,  and  so  ar- 
ranged that  the  rotating  surface  of  the  drum  turns 
away  from  the  tracing  point  of  the  lever  rather  than 
toward  it. 

4.    Observations. 

(1)  Note  whether  the  curve  is  a  simple  one  or  com- 
posed of  a  major  wave,  with  crests  superimposed 
upon  it. 

(2)  In  either  case  closely  observe  the  phases  of  the 
heart-cycle  and  determine  the  relation  of   each  part 


LAfiOAAro/^y  GUIDE  /X  rilYSIOLOCY.  15 

of  the  cycle  with  each  part  of  the  tracing.  If  the 
tracing  has  a  single  crest,  more  delicately  counter- 
poise the  lever  and  more  carefully  adjust  the  nar- 
row foot  of  the  lever  to  the  auriculo-ventricular 
groove  and  repeat  the  experiment. 

(3)  Take  tracings  of  the  auricle  alone.  Compare  these 
with  those  of  the  auriculo-ventricular  notch  and 
determine  the  causes  of  variation. 

(4)  Without  altering  the  counterpoise  take  a  tracing 
of  the  ventricle  and  compare  it  with  the  two  preced- 
ing curves  and  account  for  all  the  differences. 

(5)  Try  to  take  a  double  tracing  with  one  lever  foot 
resting  upon  the  auricle  and  the  foot  of  the  second 
lever  resting  upon  the  ventricle.  The  tracing 
points  must  touch  the  drum  in  a  vertical  line.  Are 
the  crests  synchronous?     If  not,  why  ? 

(tj)  If  a  time  tracing  be  added  one  may  determine  the 
time  relations  of  the  different  phases  of  the  heart 
cycle. 


III.  THE  APEX  BEAT.  THE  HEART  SOUNDS. 


1.  Appliances. — A  cardiograph  and  a  transmitting  tambour 

(Marey)  or  materials  for  constructing  them.  A 
stethoscope;  a  stand  and  support;  clamps;  a  kymo- 
graph; two  tambour  pans  Nos.  1  and  2  thin;  sheets  of 
rubber;  thread;  corks;  sealing  wax;  tambour  holder; 
straws;  needles;   parchment  paper. 

2.  Preparation. — Any  laboratory  will  have   different  forms 

of  cardiographs  for  demonstration  purposes,  but  not 
every  laboratory  is  able  to  afford  numerous  dupli- 
cates. An  expert  tinsmith  will  make  the  tambour 
pans  at  very  moderate  cost,  and  the 
student  can  do  all  the  rest.  Pans  may 
be  made  of  two  sizes  No.  1,  diameter 
5  cm.,  depth  4  mm.,  outside  diameter 
of  tube  3  to  4  mm.,  length  of  tube  3  to 
4  cm.  No.  2,  diameter  4  cm.,  depth  3 
mm.,  tube  as  in  No.  1,  see  Fig.  1.  To  make  the 
cardiograph  :  Take  a  tambour  pan  No.  1,  stretch 
the  sheet  rubber  across  the  pan  and  tie  in  place 
with  thread.  A  few  drops  of  sealing  wax  will 
keep  the  thread  in  place  after  it  is  tied.  Mount  the 
tambour  as  follows  :  From  any  well  seasoned,  close- 
grained  hard  wood  in  boards,  about  1  cm.  thick,  cut 
small  triangular  pieces  about  10  cm.  on  a  side.  In  the 
center  of  each  triangle  bore  a  hole  to  receive  a 
medium  sized  cork  (about  1.5  cm.  in  diameter)  the 
upper  edges  of  the  triangle  may  be  beveled  and  each 
corner  may  be  furnished  with  a  leg  by  screwing  into 
each  corner  from  the  lower  surface,  a  round  headed 


LASOKA/OK)    CUmi:   IX   rilYSIOLOGY. 


screw,  leaving;  about  1  cm.  of  tlie  screw  out  to  serve  as 
the  leg.  If  the  class  is  large,  the  (knionstrators 
should  prepare  these  tambour  boards  in  advance.  The 
tambour  is  mounted  by  fitting  a  cork  to  the  hole  in 
the  tambour  board,  boring  the  cork  and  pressing  the 
tambour  tube  through  the  hole  from  below  upward. 
Fix  a  button  of  cork  to 
the  membrane  with  sealing 
wax.  The  completed  car- 
diograph will  present  in 
section  the  relations  shown 
in  Fig.  2.  As  will  be  seen 
from  the  cut,  the  position  of  the  button  may  be 
varied  by  varying  its  shape  or  b}- changing  the  adjust- 
ment of  the  tambour  tube  in  the  cork. 

To  construct  a  transmitting  or  recording  tambour 
use  a  No.  2  tambour  pan,  stretch  the  rubber  less 
tightly  than  for  the  receiving  tambour  and  mount 
similarly  in  a  triangular  tambour  board,  omitting 
the  screw  legs.  Make  a  recording  needle  like  the 
frog's  heart  lever,  except  that  the  foot,  which  rests 
upon  the  middle  of  the  tambour  membrane,  may  pre- 
sent a  larger  surface.  The  cork  which  forms  the  ful- 
crum of  the  lever  should  be  fixed  to  the  tambour  board 
in  such  a  position  that  the  long  arm  of  the  lever  is 
vertically  above  a  diameter  of  the  tambour.  Any 
change  of  pressure  upon  the  air  in  the  tambour  will 
cause  the  membrane  to  rise  or  fall,  thus  producing  in 
the  tracing  point  of  the  lever  a  corresponding  rise  or 
fall  differing  from  those  of  the  membrane  only  in  their 
greater  extent.  It  is  evident  that  if  the  tube  of  the 
receiving  tambour  be  joined  to  the  tube  of  the  trans- 
mitting tambour  through  a  thick  rubber  tube  any 
movements  which   affect  the  button  of  the  first  will  be 


18  LABORATORY  GUIDE  IN  PHYSIOLOGY. 

manifested  by  a  rise  or  fall  of  the  lever  which  rests 
upon  the  second. 

J.  Ope7'ation. — Let  a  student  remove  the  clothing  from 
the  region  of  the  apex  beat  of  the  heart  and  take,  upon 
the  table,  a  recumbent  dorso-sinister  position.  Place 
the  button  of  the  receiving  tambour  upon  that  point 
of  the  thorax  most  affected  by  the  apex  beat  of  the 
heart.  The  movements  of  the  chest  wall  will  be 
faithfully  transmitted  and  magnified  by  the  two  tam- 
bours. Fix  the  recording  tambour  with  clamp,  and 
support  and  bring  into  the  above  described  relation 
to  the  kjmiograph.      (See  section  II.) 

4.    Observations. 

(1)  Note  the  exact  point  upon  the  chest  where  the 
apex. beat  is  most  distinctly  marked.  Is  it  the  same 
for  different  members  of  the  class? 

(2)  Take  several  cardiograms  from  the  same  individ- 
ual, being  careful  so  to  adjust  the  apparatus  as  to 
gain  the  maximum  excursion  of  the  lever.  What 
features  have  all  of  these  tracings  in  common? 
What  features  seem  to  be  accidental  and  nones- 
sential? What  is  the  cause  of  the  essential  feat- 
ures ?  What  are  the  sources  of  the  nonessential 
features  ? 

(3)  Take  cardiograms  of  several  individuals.  Do  all 
of  them  possess  the  features  which  seemed  essential 
in  the  first  series,  taken  from  one  individual.  If 
not,  how  would  you  account  for  the  difference  ? 

(4)  With  a  stethoscope,  whose  construction  you  have 
carefully  described  in  your  notes,  listen  to  the  heart 
sounds  while  the  cardiograph  is  tracing  the  record 
of  the  heart  movements.  Note  that  two  sounds  are 
audible  and  that  there  is   a   noticeable  pause  follow- 


LAnONA  TORY  GUIDE  J\   /'//VS/O/.OG  V.  19 

iii^'  tlie  shorter,  sharper  soniul;  let  us  call  the  sound 
which  succeeds  the  pause  the  first  sound. 

(5)  With  what  part  of  the  cardiof^rani  does  the  first 
sound  seem  to  correspond?  With  what  part  of  the 
cardio<;ram  does  the  second  sound  seem  to  corre- 
spond?    (live  reasons  for  this  correspondence. 

(6)  As  far  as  the  data  will  admit,  enumerate  causes  for 
the  first  sound  ;  for  the  second  sound  ;  for  the  es- 
sential features  of  tlie  cardiogram. 


IV.     THE  FLOW  OF  LIQUIDS  THROUGH  TUBES. 
LATERAL  PRESSURE. 

/.  Appliances. — Reservoir  with  short  discharge  nozzle 
whose  lumen  is  6  mm.  in  diameter  ;  5  pieces  of  glass 
tubing  whose  lumen  is  about  6  mm.  in  diameter  and 
whose  length  shall  be  60  cm.  ;  two  lengths  of  glass 
tubing  whose  lumen  is  about  3  mm.  in  diameter  and 
whose  length  shall  be  60  cm. ;  rubber  tubing  for  joining 
up  the  apparatus  ;  3  T  tubes  of  6  mm.  tubing  ;  short 
tube  with  capillary  point  from  each  size  of  tubing  ;  2 
one  liter  flasks  ;  2  supports;  a  light  pine  stick  about  6 
feet  long  ;  stopcocks. 
2.  Preparation. — A  resourceful  demonstrator  will  have  no 
difificulty  in  contriving  reservoirs,  [t  is  sometimes  not 
easy  to  provide  a  large  class  with  suitable  and  conven- 
ient reservoirs.  The  following  form 
has  proven  very  satisfactory  :  A  glass 
tube  about  3  cm.  in  diameter  may  be 
readily  furnished  with  a  glass  nozzle 
of  the  required  size  by  any  glass 
blower.  The  nozzle  should  be  about 
3  cm.  from  one  end  of  the  tube.  That 
end  may  be  closed  with  plaster  of 
Paris  and  filled  with  hard  paraffine 
to  the  lower  margin  of  the  nozzle 
opening.  This  reservoir  may  be  held 
^^"l__  upright  by  a  support.  When  com- 
plete it  presents  the  appearance  in- 
^e-^  dicated  in  Fig.  3. 


4— 4ii 


LAnORATORV  GVIPF.   /X  PZ/VS/o/AX,  )  .  21 

Operation. — Mark  upon  the  side  of  the  reservoir  a  point 
3G  cm.  above  the  center  of  the  nozzle,  also  a  point  04 
cm.  above  the  nozzle.  While  the  reservoir  is  filled  from 
one  flask  the  water  may  be  caught  in  the  other.      As- 
sume some  convenient  unit  of  time,  as  ten  or  fifteen 
seconds. 
Observations. — Fill  the  reservoir  to  the  height  of  04  cm. 
Allow  the  water  to  flow  from  the  nozzle  freely  into  the 
flasks.      Note  the  distance  to  which  the  jet  is  thrown 
when  the  water  begins  to  flow.      Note  distance  when 
the  upper  level  of  the  water  passes  the  30  cm.  mark  ; 
the  4  cm.  mark.     What  are  your  conclusions? 
{ci)      Velocity. — How  does  the  velocity  of  the  discharge 
vary  with  the  varying  height  of  the  column  of  water? 
Why  does  it  so  vary?       Does  it  verify  the  law  of 
Torricilli  ?       The  rate  at  which  a  fluid  is  discharged 
through    an   orifice   [better  a  nozzle]    /'//  a  reservoir  is 
equal  to  the  velocity  which  would  be  acquired  by  a  body 
falling  freely  through  a  height  equal  to  the  distance  be- 
tween the  orifice  and  the  surface  of  the  fluid. 

Recall  the  law  of  falling  bodies  :  Let  g  equal 
the  distance  through  which  a  body  will  fall  in  one 
second  under  the  influence  of  gravitation  alone,  h 
the  total  height  fallen  through,  t  the  time  in  seconds 
and  V  the  velocity;  derive  from  the  facts  the  follow- 
ing equations  : 

(1)  v  =  gt.  (2)  h=^. 
From  these  equations  derive  (3)  v  =  \2gh  ;  (ap- 
proximately =4.429^  h.)  Expressed  as  a  variation 
the  constant  may  be  discarded  and  the  variable 
would  read  (4)  v  :x^h.  Verify  the  truth  of  this 
mathematically  derived  law. 

*g=9,80J)  meters. 


32  LABOR  A  TOR  Y  G  UIDE  IN  PH  YSIOL  OGY. 

b.  Discharge. — If  we  let  D  equal  the  quantity  dis- 
charged from  the  nozzle  in  a  unit  of  time,  will  D 
var}'  with  the  velocity?  If  so,  it  varies  with  the  h. 
Does  D  vary  as  the  velocity.  If  so,  we  may  write 
D  a)y'h. 

Verify  as  follows  :  During  a  unit  of  time  allow 
the  water  to  flow  from  the  6  mm.  nozzle,  meantime 
maintaining  a  fixed  level — e.  g.,  at  64  cm. — by  pour- 
ing water  into  the  reservoir  from  a  flask.  Note  the 
amount  of  discharge  (D).  Repeat  the  experiment 
after  having  fixed  to  the  nozzle  a  VQ.xy  short  piece  of 
3  mm.  tubing.  Note  that  the  height  (h)  remains 
the  same.  Is  D  the  same  ?  Does  the  formula 
D  xy/h  express  the  facts  ?  If  not,  make  a  formula 
that  will  bear  verification. 

Derive  the  formulae  (5)  D  =  4.429  -  rVh,(6)D  xr^h 
when  r=  the  radius  of  the  discharging  tube.  x'Vt- 
tach  to  the  nozzle  one  length  of  6  mm.  tubing. 
Note  the  discharge  in  the  unit  of  time.  Attach  a 
second  length  of  the  6  mm.  tubing,  taking  care 
that  the  tubing  is  approximately  horizontal,  note  the 
discharge  in  a  unit  of  time.  What  is  your  conclu- 
sion ?  Why  does  the  discharge  increase  when  the 
length  is  increased  ? 

If  R  equals  resistance,  and  L  length  of  tubing, 
does  the  following  expression  represent  the  facts  : 
(7)  Ro)  L? 

Join  two  lengths  of  3  mm.  tubing  and  note  dis- 
charge in  a  unit  of  time.  What  is  the  variable  fac- 
tor in  this  experiment  ?  Does  a  tube  of  small  radius 
afford  more  resistance  than  one  of  large  radius  ?  If 
not,  the  discharge,  all  other  things  being  equal,  will 
vary  as  the  square  of  the  radius.  D  soi*^,  i.  e.,  the  3 
mm.  tube  would  discharge  one-fourth  as  much  in 
fifteen  seconds  as  would  the  6  mm.  tube. 


/..i/WK.rroKV  GUJP/-:  /x  riiysn)i.oGY. 


'23 


Is  the  relation  of    discliarge  to  resistance  direct 
or  reciprocal  ? 

X'crify  the   following   formula:    (S)  I)   :r,   -. 
Now  we  already  have  found  the  formula  I)  yr'sh. 
Verify  the  formula  (0)  D    >::'",'/'• 
c.    Pressure;    Disjoin  all  tubes  from  the  reservoir. 
Join  a  Tluhe  to  the  nozzle  in  this  position  j^ ;  join 
a    segment  of  large  glass  tubing  to  the  perpendic- 
ular arm  of  the  T-tube  and  support  it  in  an  upright 
position. 

(1)  Fill  the  reservoir  to  the  30  cm.  mark,  allow  the 
water  to  escape  from  the  distal  end  of  the  Ttube 
during  a  unit  of  time,  meantime  maintaining  the 
height  of  the  water  in  the  reservoir.  Carefully 
note  the  height  at  which  the  water  stands  in  the 
upright  tube — the  piezometer. 
(•2)  Repeat  with  water  maintained  at  G4  cm.  height 
in  the  reservoir. 

(3)  Join  a  length  of  large  tubing  to  the  distal  end  of 
the  T-tube  ;  repeat  the  experiment  using  only  the 
64  cm.  height. 

(4)  Join  a  T-tube  to  the  distal  end  of  the  segment 
of  tubing  just  added  and  repeat  the  experiment. 
Does  the  addition  of  the  last  Ttube  make  any 
essential  change  in  the  height,  at  which  the 
water  stands  in  piezoixeter  No.  1?  Does  the 
reading  of  piezometer  No.  2  agree  with  the  read- 
ing of  piezometer  No.  1  in  experiment  (2). 

(5)  Add  a  second  segment  of  large  tubing.  Repeat 
the  experiment.  Does  reading  of  piezometer  No.  2 
correspond  with  reading  of  piezometer  No.  1  in 
experimerit  (3 )  ? 

(G)   Add  piezometer  No.  3.  (Note  :  The  piezometers 


24  LABORATORY  GUJDE  IN  PHYSIOLOGY. 

may  be  held  in  position  by  using  the  two  supports 
and  the  pine  stick.)  Repeat  the  experiment. 
Does  reading  of  piezometer  No.  3  correspond 
with  that  of  No.  2  in  experiment  (4)  and  with  No. 
1  in  experiment  (2)?  Does  reading  of  piezometer 
No.  2  correspond  with  that  of  No.  1  in  experi- 
ment (4). 

(7)  Attach  a  large  capillary,  repeat  observations. 

(8)  Attach  a  fine  capillary  and  repeat  observations. 
What  is  the  relation  of  pressure  to  height  of 
column  ?  Does  pressure  vary  as  height  or  as  the 
square  root  of  height;  i.  e.,  which  of  the  following 
formulae  represents  the  facts? 

(10)     P  3oh. 

(10')      P  DO^h. 

What  is  the  relation  of  pressure  to  the  central  re- 
sistance (Re)  ? 

What  is  the  relation  of  pressure  to  distal  resistance. 
(Rd)? 

Which  of  the  following  formulae  represents  the  facts: 
(11)  P  :oRc. 
(11')  P  DoRd. 


V.     THE  FLOW  OF  LIQUIDS    THROUGH     TUBES, 
UNDER  THE  INFLUENCE  OF  INTERMIT- 
TENT   PRESSURE.     THE  IM- 
PULSE  WAVE. 

/.  Appliances. — Two  glass  tubes  of  about  6  mm.  lumen  and 
about  75  mm.  long  ;  a  thin  elastic  tube, —  thin  walled 
black  rubber — of  about  the  same  lumen  as  the 
glass  tube  and  about  150  cm.  long  ;  a  double  valved 
strong  rubber  bulb  (about  7.5  cm.  long)  ;  elastic  tub- 
ing, large  size  ;  very  thick  walled  rubber  tubing  for 
joining  up  the  apparatus  ;  Y-tube  ;  two  flasks,  or  water 
receptacles  ;  heavy  linen  thread  ;  a  wide  capillary  and 
a  fine  capillary  ;  a  piece  of  glass  tubing  10  cm.  long  ; 
500  cc.  graduated  C3'linder. 

2.  Preparation. — Join  the  large  elastic  tube  to  the  entrance 
valve  of  the  bulb.  Couple  the  two  glass  tubes  closely 
and  join  one  end  to  the  exit  valve  of  the  bulb.  Make 
all  joints  as  close  as  possible  and  tie  tightly  with 
thread.  Draw  a  coarse  and  a  fine  capillary  tube  from 
the  10  cm.  piece  of  glass  tubing. 

J.  Operation.  ■-  Clasp  the  bulb  in  the  hand  and  make  rhyth- 
matical  contractions  at  the  rate  of  about  fifteen  in  ten 
seconds.  The  process  will,  of  course,  pump  the  water 
from  one  flask  into  the  other. 

4.    Obseri'ations. 

a.  Intermittent  force  and  inelastic  tubes. 

(1)     Does    the    stream   of    water    which    is  ejected 
from    the    exit  tube  flow  in  a  constant  or  in    an 
intermittent  jet  ? 
(•2)     Attach  a  wide    capillary  and  repeat.      What  is 

the  character  of  the  stream  ? 

25 


26  LABORATORY  GUIDE  IN  PHYSIOLOGY. 

(3)  Attach  a  fine  capillary  and  repeat.  Note  the 
results. 

b.  Intei-mittent  Jorce  and  elastic  tubes. 

(4)  Disjoin  the  glass  tubing  from  the  bulb  and  join 
the  elastic  tube.  Work  the  bulb  as  directed 
above,  and  observe  the  character  of  the  fiow. 

(5)  Join  on  the  coarse  capillary  and  repeat,  noting 
the  change. 

(6)  Replace  the  coarse  capillary  by  the  fine  capil- 
lar)-  and  repeat.  Sum  up  the  results  and  formulate 
conclusions. 

c.  Quantitative  tests. 

("7)     How  much  water  will  be  ejected  through  a  fine 

capillar}'  tube  in  ten  seconds  in  experiment  (3)? 
(8)   How  much  through  a  fine  capillary  in  the  same 

time  in  experiment  (6). 
Note  :      In  performing  experiments  (Y)  and  (8)  great 
care  should   be  used  to  exert  exactly  the  same  force 
upon  the  bulb.      The  same  capillar}' should  be  used  in 
the  two  experiments. 

What  is  the  significance  of   these  two  experiments? 

d.  The  impulse  ivave.      Graphic  tests. 

Appliances. — Support;  cork-board  (about  8  by  10  cm.); 
small  glass  rod  about  20  cm.  long  ;  corks  ;  needles  ; 
kymograph  ;  piece  of  sheet  lead  1  cm.  wide  and  5  cm. 
long  ;  copper  wire  No.  16.  Make  a  tracing  lever  from 
the  glass  rod  by  drawing  out  one  end  to  a  rather  fine 
point  and  drawing  the  other  to  about  one-half  its 
original  diameter  and  bending  it  to  make  an  angle  of 
135.  Bend  up  1.5  cm.  of  each  end  of  the  sheet  lead 
so  that  it  will  stand  at  right  angles  to  the  middle  two 
cm.,  bore  the  cork  and  pass  the  larger  end  of  the  trac- 
ing lever  through  it.  Fix  the  cork-board  to  a  ring  of 
the   support  with    copper  wire  ;  fix  the   sheet  lead  to 


LABOKATOKY  GUIDE  IN  PHYSIOLOGY 


27 


one  end  of  upper  surface  of  the  cork-board  with  copper 
wire  and  pass  a  needle  tlirough  the  limbs  of  the  lead 
bearings  and  the  lever-cork  in  such  a  way  as  to  bring 
the  lever  over  the  middle  of  the  board.  The  com- 
pleted apparatus  will  have  the  relations  indicated  in 
the  accompanying  cut.      [See  Fig.  4.] 


^ 


tA 


(9)  If  the  finger  be  held  upon  the  elastic  tube 
while  the  bulb  is  being  rhythmatically  squeezed,  a 
series  of  impulses  or  pulsations  will  be  felt  by  the 
finger.  Place  one  finger  upon  the  elastic  tube 
near  the  bulb,  and  another  three  or  four  feet  from 
the  bulb.  Let  the  bulb  be  pumped  with  sudden, 
but  infrequent  contractions.  Do  you  note  a  dif- 
ference in  the  time  of  pulsation  felt  b}'  the  two 
fingers?  It  so,  which  is  felt  first?  Why?  What 
is  the  cause  of  the  pulsation  ? 

(10)  To  get  a  tracing  of  this  pulse,  pass  the  rubber 
tube  across  the  cork  board  under  the  tracing  lever 
[See  Fig.  4]  ;  adjust  to  kymograph  and  take 
tracing.  Vary  the  character  of  the  bulb  contrac- 
tions as  follows:  Taking  one  complete  rotation 
of  the  drum  for  each  variation  : 

(I)  Slow  initial  contraction  of  bulb  and  slow  re- 
laxation. 


28  LABOR  A  TOR  Y  G  UID  E  IN  PHYSIOl.  OGY. 

(II)  Slow  initial  contraction  of  bulb  and  quick 
relaxation. 

(III)  Quick  initial  contraction  of  bulb  and  slow 
relaxation. 

(IV)  Quick  initial  contraction  of  bulb  and  quick 
relaxation. 

(V)  Same  as  IV  with  slow  rhythm. 

(VI)  Same  as  IV  with  rapid  rhythm. 

Make  a  careful. study  of  these  tracings  and  deter- 
mine : 

First,  the  characteristic  and  essential  features. 

Second,  the  accidental  and  nonessential  features. 

Third,  what  is  the  cause  of  the  essential. 

Fourth,  what  is  the  cause  of  the  nonessential 
features. 


VI      THE  LAWS  OF  BLOON  PRESSURE  DETERMINED 
FROn  AN  ARTIRICIAL  CIRCULATORY  SYSTEH. 

/  Ap/>/ia>ues.--i:x^o  large  Y  tubes  of  about  «  mm.  lumen; 
four  medium  Y  tubes,  lumen  about  4  mm.;  eight  small 
Y  tubes,  lumen  about  2  mm.;  six  thick  walled  capil- 
lary tubes,  about  3  mm.  outside  measurement,  and 
lumen  not  to  exceed  1  mm.  These  capillary  tubes 
should  be  about  15  cm.  long.  Two  T-tubes  of  me- 
dium lumen  ;   two  medium  ^ized  glass  tubes  about  75 


5.J— ^ 'fo       :^^ 


/y^ 


cm.  long.  All  rubber  tubing  should  be  thin  walled 
and  very  elastic,  and  should  be  in  three  sizes,  corre- 
sponding to  the  glass  tubes.  Two  pieces  of  large  size, 
75  cm.  long,  and  two  pieces  about  half  that  length  ; 
four  pieces  of  medium  size,  about  40  cm.  long  ;  ten 
pieces  of  small  size  ;  bulb,  thread,  heavy  linen,  mer- 
cury, large  glass  receptacle  for  water,  two  medium 
sized  rubber  couplings. 


30  LAB  OR  A  TOR  Y  G  UIDE  IN  PHYSIOLOG  Y. 

2.  Preparation.  —  First,  make  two  manometers  whose 
distal  limb  shall  be  40  cm.  long,  and  proximal 
limb  30  cm.,  with  a  horizontal  shoulder  5 
cm.  long.  Second,  draw  out  the  two  limbs 
of  the  medium  Y  tube  until  they  are  about 
the  same  in  size  as  the  small  tubing  (see 
Fig.  6).  Third,  construct  the  artificial  cir- 
culatory system  according  to  Fig.  5. 
J.  Operation. — First,  supply  the  monometers  with  mercury 
so  that  there  shall  be  12  to  15  cm.  in  each  limb  of  the 
arterial  manometer,  and  5  to  10  cm.  in  each  limb  of 
the  venous  manometer.  If  the  class  is  not  familiar 
with  the  use  and  interpretation  of  the  manometer,  the 
demonstrator  should  lead  them  to  discover  all  of  its 
essential  features.  Second,  the  whole  system  should 
be  filled  with  water  and  freed  from  air  before  the  ob- 
servations begin.  Third,  care  should  be  taken  that  no 
stoppage  in  the  system  occurs  ;  otherwise  the  mercury 
may  be  thrown  out  of  the  manometers  and  lost. 
4..    Obse7-vatio7is. 

a.  The  manometer  (mercurial). 

(1)  Find  the  actual  pressure  when  the  mercury  in 
the  distal  column  stands  6  cm.  higher  than  that 
in  the  proximal  column. 

(2)  Find  the  pressure  per  square  cm.  where  the 
observation  is  the  same. 

(3)  Which  of  these  data  would  be  the  more  valua- 
ble to  record  ? 

(4)  After  the  arterial  circulatory  system  has  been 
freed  from  air  and  is  at  rest,  do  the  proximal  and 
distal  columns  of  mercury  stand  at  the  same  level  ? 
If  not,  why?  What  allowance,  if  any,  should  be 
made  for  this  ? 

b.  Arterial  pressjire. 


LABORATORY  CUIDE  JX  I'llVSIOlAHiY.  31 

(5)  With  capillaries  1  to  6  open  and  tubes  7  and 
8  closed,  let  one  member  of  the  division  make 
strong  rhythmatical  contractions  of  the  bulb  at  the 
rate  of  about  20  per  second.  Note  effect  on  man- 
ometer. Account  for  all  of  the  plienomena. 
c.      Venous  /pressure. 

(ti)     Note  the   effect   of    the  contraction   upon   the 
venous   manometer.      If    there   is   any  change   in 
the  manometer,  compare  in  rhythm  and  in  extent 
with  the  changes  in  the  arterial  manometer. 
(/.     Relation  of  arterial  to  venous  pressure. 

(7)     Make   ver}'  slow  contractions.     Note  results. 

(^8)  Make  rapid,  strong  contractions.  Note  re- 
sults. 

(9)  Make  rapid,  weak  contractions.     Note  results: 

(10)  Remove  the  clamps  from  vessels  V  and  8  (local 
dilation  of  arterioles)  and  repeat  experiments  7, 
8  and  9,  noting  and  interpreting  results.  What 
effect  does  a  dilatation  of  arterioles  have  upon 
venous  pressure?  What  effect  does  it  have  upon 
arterial  pressure  ? 

e.      Pressure  forniulce. 

Let:   P    =pressure,  Rd=:distal  resistance, 

Pa  =  arterial  pressure,         v     =  velocity, 
Pv  =  venous  pressure,         r     =  radius   of   vessel, 
Hd  =  strength  of  contractions, 

will  3our  observations  justify  the  following  formulae? 

1 

2 
3 
4 


Pa  xH. 

7. 

Pa  DcHxRd. 

Pv  DOH. 

8. 

Pa  X  r-. 

Pa  xRd. 

9. 

Pa  xHxRdxr. 

Pv  3cRd. 

10. 

Pa  XV. 

Pa>Pv. 

11. 

P  DcHxRdxr'x  V 

PaxPv. 

32  LABORATORY  GUIDE  IN  PHYSIOLOGY. 

Does  V  depend  upon  H,  do  Rd  and  r^  have  any  rela- 
tion  either  incidental  or   essential  ?      Would  Pa  x 
HxRd   practically  mean  as  much  as  formula   11? 
f.      Graphic  record  of  pulse  tracing  from  the  arterial  cir- 
culatory system. 

With  the  recording  apparatus  used  in  Chapter  V.  or 
with  a  sphygmograph,  or  better,  with  both  pieces 
of  apparatus,  make  tracings  of  the  pulsations  of 
the  arterial  tubes  "a"  and  "b."  (See  Fig.  5.) 
Compare  all  tracings  carefully  and  interpret  all 
the  features  of  the  record,  differentiating  the  es- 
sential from  the  nonessential,  as  before. 


Vn.     THE  PULSE,    SPHYGMOGRAPHS    AND    SPHYG- 
MOGRAHS. 

1.  Appliances.— \  sphygmosraph;  tracing  slips;  a  fish  tail 

gas  jet,  or  kerosene  lamp  ;  a  fixing  fluid  of  2  per  cent 
gum  damar  in  benzole.  If  each  division  has  a  wide 
mouthed  bottle  of  this  solution  the  tracing  may  be 
quickly  dipped,  drained  and  dried  upon  a  piece  of  fil- 
ter paper,  or  newspaper.  (A  fixing  fluid  after  this 
formula  is  excellent  for  the  kymograph  tracings.)  It 
may  be  kept  in  a  large  museum  jar  and  the  tracings 
dipped  into  it  whole,  or  in  sections. 

2.  Preparation.  —  Smoke  about  two  dozen  tracing  slips. 
J.    Operation. — The  adjustment  of  the  sphygmograph. 

That  the  sphygmograph  is  so  little  used  by  the  general 
practitioner  may  be  attributed  to  the  fact  that  hurry 
of  business,  or  some  other  cause,  has  hindered  him 
from  making  himself  thoroughl}'  conversant  with  the 
adjustment  and  use  of  the  instrument,  with  its  limita- 
tions and  with  the  interpretation  of   the  tracings. 

First.  Let  the  observer  stand  with  his  right  foot  on 
a  chair.  This  brings  his  thigh  into  a  horizontal  posi- 
tion. 

Second.  Let  the  subject  stand  at  the  right  of  the 
observer,  resting  the  dorsal  surface  of  the  left  forearm 
upon  the  observer's  knee. 

Third.  Let  the  observer  with  pencil  or  pen  mark 
the  location  of  the  radial  artery. 

Fourth.  Let  the  observer  wind  the  clockwork 
which  drives  the  tracing  paper;  adjust  the  latter  in 
readiness  for  tracing  ;  rest  the  instrument   upon    the 


34  LABORATORY  GUIDE  IN  PHYSIOLOGY. 

subject's  arm  with  its  foot    upon  the  radial  artery  and 
adjust  the  position,   tension  and  pressure,   in  such  a 
manner  as  to  obtain  the  maximum  amplitude  of  swing 
of  the  tracing  needle.      Take  the  tracing.     Study. 
4.    Observations. 

a.  The  location,  etc.,  of  the  radial  artery. 

(1)  What  are  the  relations  of  the  radial  artery  at 
the  distal  end  of  the  radius? 

(2)  How  may  the  relations  vary? 

(3)  Is  there  any  variation,  among  the  members  of 
the  division,  in  the  location  of  the  radial  artery? 

(4)  May  excessive  muscular  development  effect 
the  ease  with  which  the  artery  may  be  located 
and  its  pulsations  studied  ? 

(5)  May  excessive  deposit  of  adipose  hinder  the 
observations  of  the  pulse  ? 

(6)  May  faulty  position  of  subject  or  of  his  cloth- 
ing effect  the  pulse  ? 

b.  The  observation  of  the  radial  pulse. 

(7)  Feel  the  pulse  with  the  side  or  back  of  the 
finger  ;  then  with  volar  surface  and  tip  of  each 
finger  of  each  hand  and  note  the  finger  or  fingers 
with  which  the  feeling  is  most  acute.  It  will  be 
wise  to  always  use  these  fingers  in  all  tactile  ex- 
aminations. Their  acuteness  will  increase  with 
practice.     One    may  thus    acquire    the    educated 

touch TACTUS    ERUDITUS. 

(8)  How  much  may  be  learned  of  the  pulse  by 
means  of  the  touch  alone.  Observe  and  note  {a) 
frequency  ;  (b)  character  ;  i^c')  rhythm  ;  (d)  size  ; 
(^,)  compressibility.  (/)  What  else  may  be  de- 
termined by  this  method  ? 

(9)  Take  at  least  three  pulse  tracings  of  each  indi- 
vidual   in  the  division,      (a)     Compare    the    trac- 


LABORATORY  GUI  PI':  IX  Rf/VS/OLOGV.  35 

ings    taken    from    one    individual  ;  if  they  differ, 
determine  the  cause  of  the  difference.     {l>)     Com- 
pare tracings  of  different  members  of  the  division. 
Determine,  if  possible,  tlie   causes  of    differences. 
(10)     Does  location  or  relations  of    the  artery  effect 
the  sphygmogram  ?     Does  the  adjustment  of  the 
instrument  effect  the   sphygmogram?     Does    the 
elasticity  of  the  artery  effect   the  tracing  ?     How 
does  strength  or  rate  of  heart  beat  effect  it? 
Make  a  list  of  the  facts  regarding  the  condition  of 
the  circulatory  system  which  may  be  determined  with 
the  help  of  the  sphygmograph.      Make  a  list  of    the 
precautions    necessar}-  to  observe  in   the    use    of    the 
sphygmograph. 


VIII.    TO  DETERHINE  THE  GENERAL  INFLUENCE  OF 
THE  VAGUS  NERVE  UPON  THE  CIRCULATION. 

(Let  six  students  work  together.) 

1.  Appliances. — Student  operating  case  containing  scissors, 

scalpel,  artery  forceps,  3  serre-fines,  silver  probe;  and 
a  pair  of  barber's  clippers;  a  rabbit  board;  large  sheet 
of  heavy  paper;  sealing  wax;  cotton;  ether;  thread;  1 
Daniel  cell;  inductorium;  vagus  electrode;  2  Du  Bois 
keys;  V  wires;  stethoscope;  a  strong,  adult  rabbit. 

2.  Preparatio7is. — Let  the  six  students  be  subdivided  into 

three  groups  of  two  students  each. 


Let  group  "a"  be  responsible  for  the  anaesthesia. 
Use  the  sheet  of  heavy  paper  to  make  a  conical  hood, 
whose  spiral  turns  may  be  held  in  place  with  sealing 
wax.  Place  a  wad  of  cotton  loosely  in  the  mouth  of 
the  cone. 

Let  group  "  b  "  perform  the  operation.  Fix  the  rab- 
bit, back  downward,  upon  the  holder;  fix  the  nose  in 
special  holder  (see  Fig.  1);  with  the  barber's  clippers 
remove  the  hair  from  ventral  side  of  thorax  and  neck; 
make  hands  and  instruments  clean,  place  instruments 
in  a  shallow  basin  of  warm,  1  per  cent  carbolic  acid 
solution  ;    cut    two  or   three    ligatures  of  thread   and 

place  them  in  the  instrument-basin. 

36 


LAh'Oh'ATOA'V  GUIDE  /-V  PHYSIOLOGY.  37 

Let  group  "  r  "  arrange  the  electrical  apparatus  for 
stimulation  of  the  nerves.  Fill  the  cell  ;  join  up  with 
ke)'  in  the  priniar}-  circuit,  and  a  short  circuiting  key 
in  the  secondary  circuit.  Test  the  apparatus  to  see  if 
everything  is  in  order. 
J.    Operation. — 

Group  "^/."  (1)  Pour  2  cc.  or  3  cc.  of  sulphuric 
ether  upon  the  cotton  in  the  cone  ;  place  the  cone 
over  the  rabbit's  nose  ;  observe,  and  note  carefidly 
every  step  in  the  anaesthesia. 

(2)  Carefully  note  the  rate  of  the  heart  beat  before 
beginning  anaesthesia. 

(3)  Keep  the  cotton  moist  with  ether;  watch  the 
respiration  and  pulse,  and  be  careful  not  to  give  the 
animal  too  much  and  interrupt  the  experiment. 

Group  "^."     Wash  the  clipped  surface  of  the  throat. 

After  the  rabbit  is  completely  ana?sthetized,  make 
with  scissors  a  median  incision  through  the  skin, 
beginning  at  the  apex  of  the  sternum  and  cutting 
anteriorly  for  about  5  or  (_>  cm.,  divide  the  subcutane- 
ous connective  tissue  over  the  middle  of  the  trachea. 
Carefully  separate  from  the  median  line  on  either  side 
laterally  the  subcutaneous  connective  tissue  with  the 
associated  adipose  tissue. 

How  many  pairs  of  muscles  come  into  view? 
What  two  muscles  approach  the  median  line  to  form 
the-  apex  of  a  triangle  at  the  anterior  end  of  the 
sternum  ?  Observe  a  pair  of  thin  muscles  lying 
dorsal  to  the  muscles  just  mentioned  and  joining  in 
the  median  line  to  form  a  thin  muscle  sheet  covering 
the  trachea  on  its  ventral  side?  Wliat  muscles  are 
these  ? 

Carefully  lift  up  the  median  edge  of  the  sterno- 
mastoid    muscle    and    separate    with    the   handle  of  a 


38  LAB  OR  A  TOR  Y  G  UIDE  IN  PH  YSIOL  O  G  V. 

scalpel  or  a  seeker  the  delicate  intermuscular  con- 
nective tissue.  A  blood  vessel  and  several  nerves 
come  into  view. 

Is  the  blood  vessel  an  artery  or  a  vein  ?  How  many 
large  nerves  accompany  the  blood  vessel  ? 

Take  hold  of  the  sheath  of  the  vessel,  lift  it  up  and 
note  in  the  connective  tissue  accompanying  the  blood 
vessels  two  nerves,  one  large  and  one  small.  When 
the  artery  is  in  its  normal  position,  what  relation  do 
these  two  nerves  sustain  to  it?  Which  of  the  two 
nerves  is  external  and  which  is  dorsal  to  the  blood 
vessel?  Which  is  in  close  relation  to  the  artery? 
What  is  the  name  of  each  of  the  nerves  ? 

In  preparing  the  nerve  for  stimulation  one  should 
neither  grasp  it  with  the  forceps  nor  with  the  fingers. 
It  may  be  separated  from  the  delicate  connective  tis- 
sue in  which  it  lies  by  use  of  a  blunt  seeker.  Far 
better  than  any  metallic  instrument  is  a  small  glass 
rod  drawn  to  a  point,  curved  and  rounded  in  the  Bun- 
sen  lamp.  Prevent  the  tissues  drying  up  by  occasion- 
ally pressing  them  lightly  with  pledgets  of  cotton 
moistened  in  salt  solution  (0.6  per  cent). 

Adjust  the  electrode  carefully  upon  the  vagus  and 
see  that  no  unnecessary  tension  is  allowed  to  be  ex- 
erted upon  the  nerve.  It  is  usually  necessary  to  hold 
the  electrode  in  place  during  the  observation. 

Group  'V."  The  preparatory  step  in  making  stimula- 
tion is  the  closure  of  the  primary  circuit.  Why?  The 
next  step  is  to  ascertain  for  certain  that  there  is  an  in- 
ductive current.  How?  Now  with  the  induction  cur- 
rent, short  circuited,  how  may  you  stimulate?  Will 
it  probably  be  better  to  stimulate  with  a  strong  or 
with  a  weak  current  at  first  ?  If  with  a  weak  current 
first,  give  reason.      How  would  you  verify  your  posi- 


L.inoK'.rroA'Y  guide  lv  rnvs/oi.oGY.  39 

tion  bj'  experiment  ?    If  you  adopt  a  weak  stimulation 
at  first,  liow  will  j'ou  arrange  the  apparatus  to  obtain 
it? 
Ohservatiotis. — 

a.  AncBst/iesia. 

(1)  Are  you  able  to  make  out  different  stages  in 
anaesthesia  ? 

(2)  How  many  stages  did  your  animal  manifest  ? 

(3)  Give  the  characteristics  of  each  stage. 

(4)  What  effect  did  the  ether  have  upon  the  rate 
of  heart  beat. 

(5)  What  effect  did  the  ether  have  upon  the  respi- 
ration ? 

b.  The  stimulation  of  the  vagus. 

(6)  Stimulate  one  vagus.  Note  with  a  stethoscope 
whether  the  rate  of  the  heart  is  increased. 

(7)  Cut  both  vagi  high  up  in  the  neck.  Note  the 
rate  of  heart  beat  at  intervals  of  five  minutes  for 
fifteen  minutes. 

(8)  Stimulate  one  vagus.  Compare  the  result  with 
that  obtained  under  experiment  0. 

(9)  Will  very  strong  stimulation  bring  the  heart  to 
a  standstill  ? 

(10)  If  the  heart  was  brought  to  a  complete  stand- 
still by  the  stimulation,  will  it  start  up  again 
spontaneous!}'   when    the    stimulus    is    removed  ? 

•  Will   the   rate   reach    the  degree  of    acceleration 
observed  in  experiment  V  ? 

(11)  Sum  up  the  observations  into  a  concise  state- 
ment as  to  the  influence  of  the  vagus  upon  the 
heart. 

(NoTF.  :      Dispatch  the  rabbit  with  chloroform.") 


B.     RESPIRATION. 


IX.     EXTERNAL  RESPIRATORY  MOVEMENTS— 
INTRA=THORACIC  PRESSURE. 

/.  Appliances. — Operating  case;  clippers;  rabbit  board;  rab- 
bit ;  cone  for  anaesthesia  ;  ether  ;  kymograph  ;  cardio- 
graph, which  may,  in  this  case,  be  called  a  rabbit 
stethograph  ;  two  recording  tambours  ;  10  cm.  of  glass 
tubing,  3  mm.  lumen;  rubber  tubing  to  match. 

2.    Preparation. — 

(1)  Fix  and  anaesthetize  rabbit. 

(2)  Clip  and  shave  ventral  aspect  of  rabbit's  thorax. 

(3)  Make  thorax  of  rabbit,  instruments  and  hands 
clean. 

(4)  Prepare  a  thoracic  cannula  by  drawing  the  glass 
tube  slightly  in  the  center,  cutting  diagonally  at  the 
middle,  smoothing  diagonally  on  an  emery  stone. 

(5)  Join  a  30  cm.  piece  of  rubber  tubing  to  the  can- 
nula at  the  larger  end,  and  clamp  it  near  the  can- 
nula. 

(6)  Cleanse  cannula  thoroughly. 
J.    Operation. — 

a.      External  respiratory  movements. 

Place  the  button  of  the  rabbit  stethograph  upon  the 
ventral  surface  of  the  rabbit  as  near  as  possible  over 
the  junction  of  the  diaphragm  with  the  body  wall,  and 
a  little  to  the  right  or  left  of  the  median  line.  So  ad- 
just the  stethograph  as  to  obtain  the  maximum  excur- 
sion of  the  recording  lever.  The  stethograph  maybe 
held  in  position  through  the  agency  of  a  clamp  and 
support;    sometimes,  however,   better   results  may  be 


/..l/iOA-.l  /'(Un-  Gi'ini:    /X  rHYSlOI.OGY.  41 

secured  h\  luildiiif,'  tlie  stethograph  in  the  hands,  sup- 
porting tlie  wrists  on  the  edge  of   the  rabbit  board. 
b.    Intra  thoracic  pressure. 

Locate  an  intercostal  s|)ace'  to  the  left  of  the  ster- 
num and  opposite  its  middle  point.  Make  an  in- 
cision 0.5  cm.  long,  parallel  with  the  intercostal 
space  and  1  cm.  from  the  sternum.  Dissect  through 
the  intercostal  muscles,  taking  care  not  to  cut  the 
pleura.  Insert  the  point  of  the  glass  cannula  into 
the  wound,  press  it  carefully  through  the  pleura  into 
the  left  pleural  cavit}'  or  mediastinum  as  may  fre- 
quently chance,  turn  the  distal  end  of  the  cannula 
sharply  outward  until  the  instrument  has  a  nearly 
horizontal  position.  Pass  the  cannula  through  the 
intervening  pleural  membranes  into  the  right  pleural 
cavity.  Join  the  rubber  tube  to  a  recording  tambour 
and  unclamp.  Slowly  and  gently  manipulate  the 
cannula  until  there  is  evident  communication  through 
the  lumen  of  the  cannula  and  tube  from  the  pleural 
cavity  to  the  tambour. 

So  adjust  the  cannula  that  the  recording  lever  makes 
the  maximum  excursion.  Bring  the  levers  into  such  a 
relation  to  the  kymograph  that  the  tracing  point  of 
the  stethograph  lever  shall  be  vertically  over  that  of 
the  lever  which  is  to  record  intra-tlioracic  pressure, 
and  about  two  centimeters  from  it.  At  the  end  of 
the  observations  close  the  wounds  and  dress  it 
aseptically. 
Observations.  — 
a.      External  respiratory  movements. 

(1)  During  one  revolution  of  the  drum — 5  minutes 
— note  the  rate  and  rhythm  of  the  respiratory 
movements  as  recorded   by  the  stethograph. 

(2)  Does  the  stethogram  show  anything  more  than 
rate  and  rhythm  ? 


42  LAB  OKA  TOR  V  G  UID  E  IN  PHYSIOL  OGY. 

(3)  What  phase  of  a  respiratory  cycle  does  a  rise 
of  the  lever  indicate  ? 

(4)  What  is  the  relative  duration  of  inspiration 
and  expiration  as  indicated  by  the  stethogram. 

(5)  Does  the  stethogram  indicate  any  variation  in 
different  parts  of  the  inspiratory  act?  Of  the  ex- 
piratory act  ? 

(6)  Differentiate  the  essential  from  the  nonessen- 
tial in  the  stethogram  and  determine  as  far  as  may 
be,  the  cause  of  each. 

b.      Inlra-thoracic  pressure. 

(7)  Does  the  rhythm  of  varying  pressure  corre- 
spond to  the  rhythm  of  the  respiratory  movements? 

(8)  If  so,  does  that  necessarily  establish  the  rela- 
tion of  cause  and  effect  between  them? 

(9)  What  change  of  pressure  is  indicated  by  the 
rise  of  the  pressure  lever  ? 

(10)  What  movement  of  the  pressure  lever  corre- 
sponds to  a  rise  of  the  stethograph  lever? 

(11)  What  is  the  condition  of  intrathoracic 
pressure  during  inspiration?  During  expira- 
tion ? 

(12)  Stop  the  entrance  of  air  into  the  respiratory 
passage  by  closing  the  rabbit's  nostrils.  What 
effect  does  this  have  upon  the  respiratory  move- 
ments ? 

(13)  Is  the  intra-thoracic  pressure  affected  by  the 
experiment?     If  so,  explain  the  effect. 

(14)  If  two  phenomena  involving  the  same  matter, 
correspond  perfectly  in  their  cycles,  and  if  a 
variation  of  one  is  always  accompanied  by  a 
variation  in  the  other,  can  there  be  any  reason- 
able doubt  that  they  sustain  to  each  other  the 
relation  of  cause  and  effect  ? 


LAliOKA  TORY  GUIDE  JX  J'/J  )  S/o/.UuV,  43 

(15)  Which  of  the  phenomena  studied  is  the  cause 
and  which  the  effect?     Demonstrate. 

To  measure  intra-thoracic  pressure. 

(16)  Clamp  tlie  rubber  tube  of  the  pressure  ap- 
paratus. Replace  the  recording  tambour  with  a 
water  manometer.      Unclamp. 

Is  the  pressure  during  inspiration  positive  or  nega- 
tive, and  how  much  ? 

(17)  Is  the  pressure  during  expiration  positive  or 
negative,  and  how  much  ? 

(18)  If  the  whole  apparatus  were  filled  wiih  water 
instead  of  air  and  water,  would  it  make  any  essen- 
tial difference  in  the  result  ?  What  effect  do  the 
variations  of  tlie  intra-thoracic  pressure  have 
upon  the  circulation  ?     Upon  the  respiration  ? 


X.     RESPIRATORY  MOVEMENTS  IN  MAN. 

Appliances. — K3^mograph  ;  stethograph  ;  spirometer; 
tape  measure  ;  wooden  and  steel  calipers.  A  simple 
but  efficient  stethograph  may  be  made  as  follows  : 
Materials:  support,  three  large  clamp  holders,  iron 
rod,  8  or  10  mm.  in  diameter  and  50  cm.  long,  two 
wooden  rods,  1  cm.  in  diameter  and  40  c.  long,  a  re- 
ceiving tambour,  a  transmitting  tambour  with  support. 


2.  Preparation. — To  make  a  stethograph  :  Clamp  the 
center  of  the  iron  rod  to  a  heavy-base  support.  Clamp 
the  wooden  rods  to  the  iron  rod  so  that  they  will  extend 
out  to  one  side  of  the  iron  rod  in  a  horizontal  plane. 
(See  Fig.  8.) 

A  receiving  tambour  may  be  constructed  especially 
for  this  purpose  as  follows  :  Let  a  tinsmith  construct, 
from  small  brass  wire,  (^  —  ^  mm.  in  diameter), spiral 
springs  which  shall  present  the  outline  of  truncated 
cones  (See  Fig.  8  a.^,  and  fit  inside  the  larger  tam- 
bour pans. 


i.A/ioh'.r/'oh'v  iiuini-:  /x  riivsioi.oGY. 


4.'5 


If  the  student  be  supplied  with  tambour  pans, 
spring,  sheet  rubber,  thread,  sealing  wax  and  cork,  he 
may  construct  his  receiving  tambour  by  placing  the 
spring  in  the  tambour  pans,  stretching 
the  sheet  rubber  over  the  spring,  tying 
and  sealing.  The  now  conical  dia- 
phragm of  the  recording  tambour 
should  be  provided  with  a  cork  but- 
ton, and  adjusted  by  passing  its  tube 
through  a  horizontal  hole  near  the 
end  of  one  of  the  wooden  rods  (see  Fig.  8),  and  con- 
necting to  the  transmitting  tambour  through  a  small 
rubber  tube. 

J.  Operation. — Each  member  of  the  division  should  in  turn 
remove  all  clothing  above  the  waist  and  be  the  sub- 
ject of  observation  for  the  other  members.  In  making 
observations  with  the  stethcgraph  the  subject  should 
sit  with  his  back  or  side  to  the  table.  The  observer 
may  readily  adjust  the  stethograph  to  record  the 
changes  of  any  lateral  or  dorso-ventral  diameter  of 
the  thorax.  For  all  observations,  whether  with  the 
stethograph,  calipers  or  tape,  the  subject  should  keep 
the  parts  of  the  body  symmetrically  disposed. 

4..    Ohservations. — 
a.    Inspection. 

(1)  How  much  may  be  learned  of  man's  respiratory 
movements  by  simple  inspection?  INIake  a  care- 
ful enumeration  and  record. 

/'.    The  stethographic  ohservations. 

(2)  Adjust  the  stethograph  and  make  a  record — a 
stethogram — of  the  changes  of  the  lateral  diame- 
ter of  the  thorax  at  the  ninth  rib. 

Does  the  stethograph  show  more  than  could  be 
learned  from  inspection?      If  so,  what? 


46  LABORATORY  GUIDE  IN  PHYSIOLOGY. 

(3)  Take  a  stethogram  of  the  lateral  diameter  at  the 
sixth  rib.  How  does  it  differ  from  the  ninth  rib 
stethogram?     Why? 

(4)  Take  a  stethogram  of  the  dorso-ventral  diame- 
ter of  the  thorax  over  the  lower  end  of  the  glad- 
iolus.    Compare. 

(5)  Take  these  typical  stethograms  while  the  sub- 
ject reads  a  paragraph,  sighs,  coughs,  and  laughs. 
Account  for  the  peculiarities. 

(6)  Take  the  three  stethograms  after  the  subject  has 
taken  vigorous  exercise.  What  changes  are  to  be 
noted  ? 

(7)  After  a  similar  series  of  stethograms  have  been 
taken  for  others,  compare;  determine  the  essen- 
tial features;  give  causes  of  these. 

(8)  Seek  the  causes  of  the  differences  which  exist 
between  stethograms  of  different  individuals. 
May  they  be  accounted  for  by  stature,  condition, 
occupation  or  habit? 

c.  The  spirometer. 

(9)  Test  the  lung  capacity  of  each  member  of  the 
division.  May  differences  in  lung  capacity  be  ac- 
counted for  by  difference  in  stature,  condition,  oc- 
cupation or  habit? 

d.  The  girth  of  the  chest. 

(10)  Take  the  girth  of  chest  in  a  horizontal  plane 
over  the  nipple. 

{a.')   With  chest  in  normal  repose. 
(p.)   At  the  end  of  forced  expiration. 
(<:.)   At  the  end  of  forced  inspiration. 

(11)  Take  the  girth  of  chest  in  a  horizontal  plane 
over  the  juncture  of  the  ninth  rib  with  its  cartilage 
with  the  chest  normal,  empty  and  full. 

(12)  With  calipers   measure   (a)  horizontal  dorso- 


LABORATORY  GUll'iE  I.\  I'll  VSIOI.OGV.  47 

ventral  diameter  in  plane  of  nipples,  normal, 
empty  and  full. 

{b')  Lateral  diameter;  normal,  empty,  and  full. 

(f)  Lateral  diameter  over  ninth  rib;  normal,  empty 
and  full. 

(13)  Tabulate  results  for  the  whole  class  including 
name,  age,  height,  weight,  condition  (fat,  medi- 
um or  lean),  previous  occupation,  home,  (whether 
in  a  hilly  or  flat  country),  habit,  (whether  inactive 
or  active);  if  the  latter, what  sort  of  activity  (tennis, 
bicycle,  etc.)  Make  a  careful  study  of  this  table 
and  state  your  conclusions. 


XI.  THE  ACTION  OF  THE  DIAPHRAGM. 

1.  Appliances. — Operating  case;  clippers;  rabbit  board,  or 

dog  board;  rabbit  or  dog;  ether;  ether  cone;  absorbent 
cotton  ;  kymograph  ;  recording  tambour  ;  beaker  with 
warm  water  ;  medicine  dropper  or  bulb.  (If  a  dog  be 
used,  the  medicine  dropper  will  not  be  large  enough, 
its  place  may  be  taken  by  a  soft  spherical  rubber  bulb 
about  2  cm.  in  diameter.)  Inductorium,  1  cell,  2 
ke3's,  vagus  electrode,  5  common  wires  and  2  fine 
wires. 

2.  Preparation. — Fix  the  animal  to  the  board,  anaesthetize, 

clip  anterior  median  region  of  abdomen.  Put  the  bulb 
into  the  warm  water,  join  the  glass  tube  of  the  bulb  to 
the  recording  tambour  through  a  rubber  tube.  This 
apparatus  thus  joined  may  be  called  a  phrenograph 
and  its  record  a  phrenogram. 

Set  up  electrical  apparatus  with  short  circuiting  key 
in  secondary  coil. 
J.  Operatioti. — From  the  posterior  extremity  of  thexyphoid 
appendix  make  a  median  incision  through  the  abdomi 
nal  walls  from  3  cm.  to  5  cm.  according  to  the  size  of 
the  animal.  Clamp  with  your  serre-fines  any  small 
vessels  which  may  be  oozing.  After  having  clamped 
the  rubber  tube,  which  connects  the  bulb  to  the  tam- 
bour, carefully  insert  the  warm,  wet  bulb  between  the 
diaphragm  and  the  liver.  The  liver  will  usually  afford 
sufficient  resistance  to  cause  alternate  compression 
and  relaxation  of  the  bulb  and  a  consequent  rise  and 
fall  of  the  recording  lever;  if  such  be  not  the  case,  the 
liver  may  be  held  in  place  by  two  fingers  inserted  into 


LABORATORY  GUIDE  /X  PHYSIOLOGY 


19 


the  wound.     In  the  meantime  let  another  member  of 
the  division   dissect  out  the  left  phrenic  nerve.     Fig. 
9  shows  the  relation  of  the  phrenic  at  the  base  of  the 
neck,  in  the  rabbit. 
./,    Observations. — 

a.      Tactile  observation  of  the  diaphragm, 

(1)      In  what  condition  is  the  diaphragm  during  in- 
spiration ?     Expiration  ? 


(2)  In  what  position  is  the  diaphragm  during  these 
two  phases  of  respiration? 

(3)  What  parts  of  the  diaphragm  make  the  great- 
est change  of  position  during  inspiration? 

(4)  What  causes  the  diaphragm  to  arch  anteriorly 
during  normal  expiration  ?  During  the  present 
observations? 


50  LAB  OR  A  TOR  \ "  G  UIDE  IN  PH  YSIOL  O  G  Y. 

(5)  Are  the  diaphragmatic  movements  synchronous 
with  the  costal  movements? 

b.  The  normal phreno gram. 

(6)  Take  a  phrenogram.  What  may  be  learned 
from  it? 

(7)  Without  varying  the  adjustment  of  the  phreno- 
graph  bulb,  take  a  tracing  while  repeatedly  inter- 
rupting the  respiration  by  holding  the  nostrils. 
What  does  the  phrenogram  show?  What  is  the 
interpretation  ? 

If  you  had  taken  a  tracing  of  intra-thoracic  pres- 
sure, what  would  it  have  shown? 

c.  The  phre7iic  fierve  a?id  its  functtoft. 

(8)  Describe  minutel}'  the  relations  of  the  nervus 
phrenicus  in  the  neck. 

(9)  Cut  the  nerve  while  tracing  a  phrenogram 
from  the  left  side  of  the  diaphragm.  Note  the 
result. 

(10)  Take  a  phrenogram  from  the  right  side  of  the 
diaphragm.  Does  it  differ  essentially  from  the 
normal? 

(11)  While  taking  a  left  phrenogram  stimulate  the 
distal  end  of  the  left  phrenic  nerve.  Interpret 
the  result. 

(12)  While  taking  a  right  phrenogram  stimulate 
the  distal  end  of  the  left  phrenic  nerve.  Interpret 
the  result. 

(13)  Dissect  out  and  cut  the  right  phrenic   nerve. 
Does  the   diaphragm  cease  to  move  ?     If    it  moves, 

is  its  movement  active  or   passive  ?     Account  for 
the  phenomena. 
Kill  animal  with  chloroform. 


XII.     a.      RESPIRATORY  PRESSURE. 

B.     STinULATION  OF  PUL/VIONARY  VAQU5 
THROUGH   INCREASE  OF  INTRA=PUL- 
MONARY  PRESSURE. 

/.  Appliances. — Operating  case  ;  clippers  ;  rabbit  board  ; 
ether  ;  ether  cone  ;  absorbent  cotton  ;  rabbit  stetho- 
graph  ;  kymograph  ;  a  small  mercury  manometer,  to 
the  proximal  limb  of  which  is  attached  a  thick  walled 
rubber  tube,  a  piece  of  glass  tubing  for  a  mouthpiece; 
a  screw  clamp. 

2.  Preparation. — Fix  and  anaesthetize  the  rabbit,  and  clip  the 
ventral  surface  of  the  neck.  Join  up  the  manometer 
as  shown  in  Fig.   10. 

2-  Operation. — Make  a  longitudinal  incision  over  the 
trachea.  Carefully  pass  a  strong  linen  ligature  under 
the  trachea.  Make  a  median  ventral  slit  in  the 
trachea  anterior  to  the  ligature.  Pass  through  the 
slit,  the  limb  of  the  Y-tube  marked  1.  (Fig.  10.) 
Ligate. 

-/.    Observations. 

a.  Respiratory  pressure. 

(1)  After  the  ligature  is  tied  how  does  the  rabbit 
breathe  ?  Are  tlie  thoracic  and  abdominal  move- 
ments of  respiration  accompanied  by  other  res- 
piratory movements  ? 

(2)  Witli  tube  "n  "  (see  Fig.  10)  open  is  there  any 
variation  of  the  mercur\'  during  respiration? 

(3)  With  a  screw  clamp  slowly  close  tube  "  n."  As 
the  resistance  to  the  tiow  of  air  increases  what 
change  is  noted  in  the  manometer  ? 


52 


LABORATORY  GUIDE  IN  PHYSIOLOGY. 


(4)  Quickly  clamp  tube  "n  "  at  end  of  expiration 
and  carefully  note  the  manometer  reading.  Is  it 
positive  or  negative  ? 

(5)  Clamp  tube  "  n  "  at  the  end  of  inspiration.  Is 
the  pressure  positive  or  negative  ? 

(6)  You  have  been  determining  certain  facts  regard- 
ing RS3PIRAT0RY  PRESSURE.  Are  the  causes  of  the 
changes  of  respiratory  pressure  the  same  as  the 
causes  of  the  changes  of   intra-thoracic  pressure? 

(7)  In  what  way  does  respiratory  pressure  differ 
from  intra-thoracic  pressure  ? 

Stiviulation  of  the  pulmonary  vagus. 


nj.io 


» 

u 


Centimeter 
Scale 


(8)  Count  the  pulse.  Adjust  the  stethograph,  and 
mouth  over  the  glass  mouthpiece;  quickly  blow  in- 
to the  tube  "  n  "  until  the  manometer  indicates  two 
during  the  tracing  of  a  stethogram  place  the 
centimeters  of  intra-pulmonary  pressure  ;  clamp, 
count  the  pulse.  After  a  few  seconds  release  the 
clamp  and  let  the  rabbit  breathe  normally  for  a 
few  minutes. 

Repeat  the  experiment.  Vary  by  producing  in  turn 
3  cm.,  then  4  cm.  and  finally  6  cm.  of  intra-pul- 
monary  pressure.  Fix  the  stethogram  and  com- 
pare. 

(9)  Compare  your  results  with  those  obtained  from 
other  rabbits.      What  are  the  essential  features  of 


LAJWK.-nOKY  CUIDI-:  AV  Pin  SIOLOGV.  5)} 

the  modified  stethogram  ?     Formulate  the  results. 

(10)  What  effect  has  a  sudden  increase  of  intra- 
pulnionar}'  pressure  upon  the  rate  of  the  heart's 
action. 

(11)  What  nerve  is  tlistrihuted  to  both  lun^s  and 
heart?  Admitting  that  it  is  possible  for  the  ob- 
served effects  to  be  produced  through  the  agency 
of  the  nerves  just  named,  state  how  this  action 
may  be  accomplished. 

(12)  Could  the  effects  be  produced  in  any  other 
way  than  in  that  which  you  have  given  ? 

(13)  Is  the  demonstration  unassailable,  if  not, 
what  experiments  would  lead  to  results  conclusive 
for  or  against  the  theory  ? 

(14)  Is  the  minimum  intra- pulmonary  pressure, 
which  typically  modified  the  stethogram,  greater 
or  less  than  the  respirator}'  pressure  of  forced 
expiration  ? 

(15)  What  effect  upon  intrathoracic  pressure 
would  the  induction  of  high  intra-pulmonary 
pressure  have  ? 

(IG)  What  effect  upon  blood  flow  would  high  intra- 
pulmonary  pressure  accompanied  by  repeated 
acts  of  forced  expiration  have  ?  WHiat  incident 
effect  upon  the  rate  of  heart  beat  ? 


XIII.     RESPIRATION    UNDER    ABNORMAL    CON= 
DITIONS. 

1.  Appliances. — Three    small    animals,    e.    g.,    mice,   rats, 

guinea  pigs  or  squirrels.  Two  wide-mouthed  bottles 
or  jars  which  may  be  sealed;  scales  or  large  balances; 
CO3  generator;  water  bath;  operating  case;  dissect- 
ing boards. 

2.  Preparation. — Determine    the    weight    of    each  animal. 

Choose  a  receptacle  whose  cubic  contents  is  about 
three  to  five  times  as  many  c.  c.  as  the  weight  of 
animal  "a"  in  grams.  Choose  second  and  third  re- 
ceptacles whose  contents  represent  about  15  to  18  c.  c. 
to  one  gram  of  animals  "b"  and  "c,"  respectively. 
J .    Operation.  — 

I.  Preliminary. 

b.  Put  animal  "b"  into  jar  "b."  Before  closing 
count  respirations  ;    close  air-tight. 

c.  Fill  jar  "c"  one-third  full  of  water  and  displace 
the  water  with  COg.  Put  animal  "c"  into  the 
jar,  taking  care  to  allow  as  little  loss  of  CO3  as 
possible  ;    close  ;    count  respirations. 

a.  Put  animal  "a"  into  the  small  jar  "a";  count 
respirations;    close  the  jar. 

II.  Post-mortem  examination. 

After  an  animal  dies  fix  it  to  the  dissecting  board 
and  open  the  abdominal  and  thoracic  cavities; 
take  great  care  not>tocut  a  large  blood  vessel; 
pin  the  flaps  out  so  that  all  of  the  organs  will  be 
exposed  and  in  place. 
4.    Observations. — 

a.  Respiration  in  small  closed  space. 

54 


LABOKATORY  GUIDE  IX  /•// VS/OLOGY.  55 

(1)  Make  careful  record  of  number  of  respirations 
and  general  condition  of  animal  "a"  in  the  nor- 
mal state,  and  at  the  end  of  every  five  minutes 
after  the  closure  of  the  jar. 

What  changes  in  rate  or  depth  of  respiration  have 
been  noted  ? 

(2)  Note  all  abnormal  signs  and  symptoms. 

(3)  On  post-mortem  examination  record  condition 
of  heart,  large  blood  vessels,  lungs,  liver,  kidneys 
and  of  the  general  appearance  of  the  tissues. 

(4)  Compare  the  conditions  with  those  found  in 
a  normal  animal,   prepared  bj'  the  demonstrator. 

d.  Respiration  in  a  larger  closed  spact. 

(5)  Note  all  symptoms  of  animal  "b"  every  five 
minutes  after  confinement  in  the  jar. 

(6)  Make  a  post-mortem  examination  ;  record  in 
detail  the  condition  of  the  organs  as  in  the  case 
of  animal  "  a." 

(^7)     Compare  animal  "b"  with  the  normal  animal. 

(8)  Compare  animal  "  b  "  with  animal  "  a. " 
c.   Respiration  in  an  atmosphere  of  one-third  CO.^. 

(9)  Note  all  symptoms  at  intervals  of  five  minutes. 

(10)  Compare  these  observations  with  correspond- 
ing ones  from  animal  "a"  and  animal  "b." 
Wliat  are  your  conclusions? 

(11)  Make  a  post-mortem  examination;  make  a 
record  as  before. 

(12)  Compare  appearances  in  animal  "c"  with 
those  in  the  normal  animal  ;  with  those  of  animal 
"a  ;  "    with  those  of  animal  "  b." 

(13)  Make  a  generalized  statement  of  the  facts 
discovered  in  the  experiments. 

(14)  What  is  the  cause  of  death  when  an  animal 
is  inclosed  in  a  small  space? 


56  LABORATORY  GUIDE  IX  PHYSIOLOGY. 

(15)  What  is  the  cause  of  death  when  an  animal 
is  inclosed  in  a  large  space  ? 

(16)  Have  the  relations  which  you  have  discovered 
any  bearing  upon  the  future  development  of 
animal  life  upon  the  earth? 


XIV.     RESPIRATION  IN  ABNORMAL  MEDIA. 

/.  App/iancfs.— Three,  small  animals  ;  three  jars  ;  water 
bath;  hydrogen  generator;  large  test  tube  of  hard 
glass;  support  with  tube  clamp;  Bunsen  burner; 
delivery  tube;  bichromate  of  potassium;  ammonium 
chloride;    operating  case;    dissecting  boards. 

2.  Preparation. — Construct  a  nitrogen  generator  as  indi- 
cated in  Fig.  11. 


^^         Ti$.tl 


?.    Operation. — 

I.    Preliminary. 

a.  Fill  a  jar  full  of  water;  displace  the  water  with 
nitrogen,  generated  from  0  gms.  of  powdered 
KgCrgO,  +  3  gms.  of  NH^Cl  in  the  apparatus 
shown  in  Fig.  11.  Put  animal  "a"  into  the 
atmosphere  of  nitrogen;    close  the  jar. 

b.  Fill  a  jar  full  of  water,  displace  it  with  hydrogen 
gas.     Put  animal  "  b  "  into  the  jar  and  close  it. 

c.  Fill  a  jar  one-third  full  of  water;  displace  the 
water  with  illuminating  gas.  Put  animal  "c" 
into  the  jar  and  close  it. 

57 


58  LABORATORY  GUIDE  IN  PHYSIOLOGY. 

II.   Post-mortem  examination — See  XIII.  3  II. 

4.    Observaiiofis. — 

a.  Respiration  in  afi  atmosphere  of  nitrogen. 

(1)  Note  all  symptoms. 

(2)  How  do  these  compare  with  those  of  death  by 
oxygen  starvation  ? 

(3)  Record  post-mortem  appearances. 

(4)  Compare  with  previous  cases. 

b.  Respiration  in  an  atmosphere  oj  hydrogen. 

(5)  Note  carefully  every  abnormal  appearance 
and  symptom. 

(6)  Make  a  record  of  the  post-mortem  appearances. 

(7)  Compare  these  with  the  appearances  after 
death  by  oxygen  starvation;  by  CO.,  narcosis. 

c.  Respiration  in  an  atmosphere  of  one -third  illuminating 
gas  (C6'+). 

(8)  Record  all  symptoms. 

(9)  Record  post-mortem  appearances. 

(10)  How  does  death  in  an  atmosphere  of  CO 
compare,  as  to  symptoms,  with  death  in  an  at- 
mosphere of  nitrogen  ? 

(11)  Compare  it  in  turn  with  other  forms  of  death 
as  induced  in  XIII.  and  XIV. 

(12)  Compare  the  post-mortem  appearances  in 
this  case  with  those  in  preceding  cases. 


QP44 


II14 


Hall 


A  laboratory  guide  in  physiology 

Chap.  I- II.  On  circulation  and 
respira+ion. 


\ 


rt.VHfc'i'TlTi-, 


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